Miniature plug receptacle



Dec. 13, 1960 p, N, LEHR ETAL 2,964,725

MINIATURE PLUG RECEPTACLE Filed Nov. 9, 195e IN V EN TORS PHILIP N. LEHR 8u GUS CARLSON mi@ A Tram/fw.

United States Patent() MINIATURE lPLUG RECEPTACLE Philip N. Lehr, Huntington, and Gus Carlson, Flushing, N.Y., assignors to Dictograph Products, Inc., a corporation of Delaware -Filed Nov. 9, 1956, Ser. No. 621,456

4 Claims. (Cl. 339-59) This invention relates to plug'receptacles and more particularly to miniature plug receptacles as might be used, for exampleQin connecting hearing aid components and capable ofv withstanding hard use without loss in electrical and mechanical efficiency.

In a relatively sensitive instrument such as a hearing aid, eicient electrical connections are required between the power and transducer components to prevent distortion and noise. Not only must the connections be able to withstand repeated making and breaking over the life of the hearing aid but from time to time they are inadvertently subjected to severe strains. Imposed on these rather critical design criteria is the need for making the parts small and inconspicuous, which factors are not necessarily compatible with the electrical and mechanical demands placed on the instrument.

In accordance with the present invention, there is provided a miniature plug receptacle which is electrically and mechanically eilicient while at the same time extremely small in size, one dimension barely exceeding the size of the plug elements which it is designed to receive. Each metallic contact element which receives a lprong of the plug is made resiliently expansible, as by slitting, and is tightly embraced, in the direction of expansion, in a channel in a housing of resilient plastic. In this fashion the entering prong element of a plug resists the combined resilience of the metallic contact element and the resilient plastic housing. Each contact element can take the form of an elongated sleeve having an offset wall portion along its length to secure the sleeve against axial movement in the housing and the housing, with the sleeves in place, can be secured to the chassis or other supporting surface of the hearing aid to` cover the channels. In this fashion the chassis or other part of the hearing aid becomes, in effect, one part of the plug.

A representative embodiment of the invention is described below having reference to the accompanying drawing in which:

Figure l is an end view of a plug receptacle; and

Figure 2 is a View in section taken on the line 2 2 of Figure 1 looking in the direction of the arrows.

Referring to the drawing, the invention is illustrated as embodied in a plug receptacle including a central body or base portion 11 of generally flattened shape and formed, preferably in a single piece, of a tough resilient plastic, such for example as nylon. Formed in one surface of the base portion 11 are a pair of elongated channels 12 and 13 having a depth which amounts to a substantial portion of the thickness of the base. 'Ihe channel 12 is bounded by opposed sidewalls 12a and 12b and the channel 13 by opposed sidewalls 13a and 13b, the opposed sidewalls being generally at for approximately one-half of the channel depth and convergent thereafter along a generally cylindrical surface to define a rounded bottom. The center portions 12C and 13e of the channels 12 and 13, respectively, are enlarged and the thickness of material beneath the channels, in the areas near the ends of the channels identified by the 2,964,725 Patented Dec. 13, 1960 ICC numerals 14 .and 15, is reduced so that a certain degree of flexing of the base portion can take place, all as described below.

The channels 12 and 13 include throat portions 16 and 17, respectively, part of one side of each 'of the throats being relieved by means of holes 18 Vand'19, respectively, formed in the base portion 11. For purposes of mounting the plug receptacle 10, the central base portion 11 can be anked by attened wings 20 and 21 carrying apertured mounting lugs 22 and 23, respectively, at their extremities. f

Received in the channels 12`and 13, respectively, are a pair of metallic sleeve elements 24 and'25. The forward ends 24a and 25a of the sleeves comprise the contact portions and are formed with longitudinal slots 24h and 25b and inwardly oiset or indented portions 24o and 25e, respectively. Intermediate their ends and beyond the contact portions 24a and 25a the sleeves are formed with deeply indented or necked-down portions 24d and 25d corresponding generally in shape to the throat portion 16 and 17 of the base. The back end of the sleeves 24 and 25 are formed with tubular portions 24e and 25e which can serve as wiring or contact terminals. The sleeves 24 and 25 are pressed into the channels 12 and 13, respectively, with the end portions of the sleeves tightly wedging in the relatively narrower end portions of the resilient base and with clearance occuring between the channel sidewalls and the sleeves elsewhere. Preferably, the slots 24h and 25h are disposed in a generally vertical plane although they can also be disposed in a horizontal plane. Securing means which can take the form of pins or screw shanks 18a and 19a are inserted in the holes 18 and 19 to anchor the sleeves. In this fashion, the sleeves are tightly gripped in the channels and are absolutely secure against axial slippage 1n use.

It will be understood that the resilient base is not stressed to its extremes by the placement of the sleeves and that, therefore, the base and the sleeves present their combined resilience to the prongs of the plug connector P, shown in phantom lines. The sleeves are resilient by virtue of the slots 24b and 2517 in the contact portions and the base is resilient by virtue of its inherent resilience, augmented by the relatively narrow flexing portions 14 and 15. Inwardly of their ends, the sleeves are able to expand in the clearance space afforded by the enlarged portions 12C and 13e` of the channels 12 and 13. As stated, the sleeves are secured against axial movement by means of the throat portion of the base entering the indented portions 24d and 25d of the sleeves and the securing means 18a and 19a in the holes 18 and 19. The prongs of the plug P can be held in place in the receptacle by means of the indented portions 24:.` and 25C entering undercut portions of the prongs behind their tips.

'Ihe receptacle unit 10 is completed by mounting on a surface, such as the chassis 30 by means of screws 22a and 23a passing through the mounting lugs 22 and 23. The chassis, which is preferably formed of insulating material, then becomes part of the plug assembly and contributes to the minimizing of the space required for the unit. Other holes 26, 27, 28, and 29 can be formed in the base for purposes of mounting, carrying other parts, or the ilke.

It will be understood that the invention can take various other forms and arrangements within the scope of the present invention. Thus, for example, the sleeves 24 and 25 can be double ended, having prong-receiving contact portions at both ends. Also, the general shape and mounting arrangement of the base can be adapted for particular installations. The invention should not,

therefore, be regarded as limited except as defined in the following claims.

We claim:

'1. A miniature Y.plug receptacle assembly comprising a attened resilient plastic base, at least a pair of paral lel, elongated, open channels formed in Vone surface of the base, the channels being separated by a ridge of plastic, means forming at least one throat Aportion in each channel, metallic ,plug-receiving sleeves received respectively in the channels, each sleeve including an indented portion to -receive the throat portion of the channel, said sleeves each .including a contact ,portion tightly received in its channel to press against the side walls thereof, said sleeves being longitudinally slit to be expandable against the side walls of the channel, whereby a Eplug element forced into the contact portion of the sleeve spreads thesleeve against the combined resilience of the slit sleeve and the plastic base, an inwardly extending bulge inthe contact portion adapted to be received in a lrelieved portion on the shank of the plug element to hold the latter in place, and an extension portion on each sleeve beyond the throat portion atording contact terminal means.

2. A plug receptacle as set forth in claim 1, said base having apertures formed therein, each intersecting a portion of a channel at the throat portion, and securing pin means received in the apertures.

3. A plug receptacle as set forth in claim 1, said sleeves and channels being relatively proportioned to afford vlateral clearance between the sides of the sleeve and the sides of the channel intermediate their ends.

4. A plug receptacle as set forth in claim 1, including insulating wall means, and means to secure the base against the wall means to close the channels along their lengths.

References Cited in the le of this ,patent UNITED STATES PATENTS 1,026,269 Knauff May 14, 1912 2,310,142 Woodman Feb. 2, 1943 2,428,214 Gorey Sept. 30, 1947 2,454,803 Israelski -t Nov. 30, 1948 2,490,317 Ostrak a Dec. 6, 1949 2,563,713 Frei Aug. 7, 1951 2,754,373 Shaper July 10, 1956 FOREIGN PATENTS 114,988 Switzerland May 17, 1926 

